X-ray Photoelectron Spectroscopic Investigation of the Chemical Reactivity at Ni/CuO Interface

The chemical reactivity at the Ni/CuO interface has been investigated. Thin films of nickel were deposited on CuO substrates by the e-beam technique. The deposition was carried while the CuO substrate was kept at room temperature. The interface has been characterized in situ by the technique of x-ray photoelectron spectroscopy. In this technique, the aluminum anode has been used as the source of x-ray energy. The Ni 2p and Cu 2p regions were recorded. The binding energy positions, the full-width-at-half max, and the high binding energy satellites associated with the core level peaks have been utilized to identify the chemical states of Ni and Cu. The spectral features show considerable reactivity between Ni and CuO. The Ni has been observed to get oxidized to NiO while CuO got reduced to elemental copper. The data show presence of NiO and elemental nickel at the interface. The width of the interface has been estimated from the spectral data. The interaction has also been investigated as a function of substrate temperature. The results will be beneficial in understanding the behavior of the NiO/Cu interface.